The effect of minor components on the frying stability of regular and modified vegetable oils

Abstract:

A study was conducted to compare the relationship between frying stability and levels and degradation rates of selected minor components in regular and modified canola, soybean and sunflower oils. Oils evaluated included regular (RCO), high oleic (HOCO), high oleic low linolenic (HOLLCO) and low linolenic (LLCO) canola oils; regular (RSY) and low linolenic (LLSY) soybean oils; and regular (RSO) and high oleic (HOSO) sunflower oils. Oils were heated at $175\pm2\sp\circ$C for a total of 72 hours, with french fries fried in the oil intermittently. Frying stability was compared based on rates of formation of free fatty acids (FFAs) and total polar components (TPCs). The results of the current study showed that fatty acid composition was not the sole determinant of frying stability in these oils. Variations in tocopherol levels and degradation rates among the oils appeared to explain some of the differences in frying stability. The beneficial effect of high oleic acid levels in HOSO was lost due, in part, to much lower levels and faster degradation rates of tocopherols. Consequently, predicting frying stability on the basis of fatty acid composition alone is inadequate when other minor components such as tocopherols are not taken into consideration. (Abstract shortened by UMI.)